Containers made from or utilizing expanded polystyrene or other expanded polymers as an insulating medium have been in use for many years. Polystyrene is considered a suitable insulating material for many applications. However, its wide acceptance has made polystyrene a nuisance to dispose of because of the difficulty of disposing in an environmentally responsible manner. Polystyrene is generally not as easily recyclable by consumers compared with, for example, OCC (old corrugated cardboard). Most cities now have recycling programs that will pick up consumer's OCC and other recyclables, such as glass, directly from a consumer's home. However, many of these programs exclude expanded polystyrene. If the consumer wishes to recycle expanded polystyrene, the consumer must usually travel a long distance in order to dispose of their expanded polystyrene. The sorting of expanded polystyrene from recyclables produces much waste in terms of hours spent in sorting and hauling away expanded polystyrene. Also, if the expanded polystyrene is not recycled, it will most likely end up in a landfill, where its expanded volume takes up a considerable amount of landfill space. The properties that make expanded polystyrene a good insulating material include being lightweight, being water resistant, having a high insulating value, and being generally inexpensive to manufacture. However, expanded polystyrene also has certain drawbacks, such as being fragile.
Containers made from fibreboard, which is a cellulose-based product, are widely used in many applications as well. However, to date, containers made from fibreboard have not been specifically desirable as insulating materials. This was partly due to the fact that if fibreboard becomes wet, fibreboard will lose its strength and is prone to tearing. While many attempts have been implemented for sealing fibreboard containers from moisture penetration, the methods that were tried proved to be less than satisfactory.
In U.S. application Ser. Nos. 10/879,846; 10/880,008; 10/879,268; and 10/879,821, the assignee of the present invention described methods for producing a cellulose-based substrate encapsulated with a polymeric film that is recyclable and moisture resistant.
However, there is still a need for products that may replace expanded polystyrene, for example, and methods to develop encapsulated cellulose-based substrates into suitable replacements for many applications now using expanded polystyrene. The present invention solves this problem and has further related advantages.